Cellular Energetics and Metabolism

Flashcards covering key vocabulary and concepts from the lecture on cellular energetics, catabolic metabolism, glycolysis and related topics.

Cellular Metabolism

Occurs in a series of small enzyme catalyzed steps to capture energy efficiently.

Catabolic Reactions

Break down larger molecules into smaller ones, often to extract stored energy.

Anabolic Reactions

Build up smaller molecules into larger ones, requiring energy input.

Glycolysis

The breakdown of glucose, occurring in the cytosol.

Citric Acid Cycle (Krebs Cycle)

The breakdown of glucose, occurring in the mitochondria.

Oxidation

The removal of electrons; in metabolism, it often involves oxidizing the carbons of glucose.

Oxidative Phosphorylation

Process by which a proton gradient across the mitochondrial membrane is used to synthesize ATP.

Metabolic Interconnectedness

Metabolism is highly interconnected, where reactions influence many other reactions within the cell.

Cellular Energy Source

Almost always comes from the chemical breakdown of nutrients, even if the ultimate energy source is sunlight.

Carbon Oxidation

Releases energy because carbon is generally in a lower energy state when more oxidized.

Activation Energy

The amount of energy required to start a reaction, reduced by enzymes to allow reactions at ambient temperatures.

Enzyme-Managed Oxidation

Oxidation of glucose in small steps, reducing activation energy and allowing energy capture in chemical forms (ATP).

Activated Carrier Molecules

Specialized molecules like ATP and Acetyl CoA that capture energy in an intermediate form during metabolism.

ATP

Major currency of cells, serving as a common energy exchange molecule.

NADH

A form of chemical energy, often referred to as reducing power, carries high energy electrons.

Glycolysis Phases

Investment Phase (invest two ATPs), Cleavage Phase (split glucose), and Energy Generation Phase (generate four ATPs).

Coupled Reaction

A reaction where the energy from oxidation is used to power energetically unfavorable reactions like ATP generation.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH)

Enzyme that performs the first part of the reaction by forming a covalent bond with glyceraldehyde 3-phosphate.

Substrate-Level Phosphorylation

Process where a phosphate group is first attached to an organic molecule, then transferred to ADP to make ATP.

Oxidative Phosphorylation

Process where inorganic phosphate is directly attached to ADP to make ATP with no organic intermediate.

Muscle Cell

Synthesizes ATP in the mitochondria, faces limitations in ATP transport.

Fermentation

Process that regenerates NAD from NADH when molecular oxygen is absent, enabling glycolysis to continue.